The proposed study builds on our findings from a previous clinical trial that demonstrated the effectiveness of collaborative care for older adults with Alzheimer's disease cared for in primary care practices. In the prior trial, we demonstrated that guideline-level medical care resulted in improved quality of care and improved behavioral and psychological symptoms over one year among patients and their caregivers. However, despite finding significant differences among study groups on Neuropsychiatric Inventory scores, we did not find a significant difference between groups in functional decline. Both study groups experienced a significant decline in function over 18 months. The current study proposes to test a home-based intervention specifically designed to slow the rate of functional decline among older adults with Alzheimer's disease. In addition to building on our past research, the study also builds from recently reported research which demonstrated the short-term efficacy of home-based occupational therapy interventions among older adults with dementia. These trials show that older adults with dementia, including Alzheimer's disease, can both participate in and benefit from occupational therapy-based interventions delivered in the home. The specific aim of this study is to conduct a two-year, randomized, controlled clinical trial to improve functioning among older adults with Alzheimer's disease by comparing a control group receiving best practices primary care with an intervention group receiving best practice primary care plus a home-based occupational therapy intervention. We will test the primary hypothesis that subjects with Alzheimer's disease in the intervention group will have improved function at two years compared with the best practice primary care control group.